Centrifugal bowl for separating heavy sludge and solids from lighter liquids



Dec. 3, 1935. G. J. s'rREzYNsKl 2,022,815

Y CENTRIFUGAL BOWL FOR SEPARATING HEAVY SLUDGE AND SOLIDS FROM LIGHTER LIQUIDS 'I Filed Oct. 20, 1935 Patented Dec. 3, 1935 PATENT OFFICE CENTRIFUGAL BOWL FOR SEPRATING HEAVY SLUDGE AND SOLIDS4 FROM LIGHTER LIQUIDS George J. Strezynski, Poughkeepsie, ,.N. Y.; as-

signor to The De Laval Separator Company, New York, N. Y., a corporation of `New Jersey Application October 20, 1933, Serial No. 694,398 9 Claims. (Cl. 233-20) In an application led by me September 27, 1933, Ser. No. 691,111, there is disclosed a floating valve which is radially movable outward to close an outlet in the bowl wall for escape of a heavy separated substance and is radially movable inward to open said outlet. In one specific embodiment of the invention the operation is automatically controlled inA that the valve is caused to open after heavy solids, or a heavy liquid, have accumulated to a vpredetermined thickness on the bowl wall, and to clos'eafter more or less of said heavy constituent has been expelled through said outlet. In another specic embodiment of the invention, the closing of the valve is under the control of the operator. In each embodiment the movement of the valve is controlled by admitting liquid to theinterior of the valve to increase its weight sufliciently to overcome the buoyant effect. In one embodiment the admitted liquid is a lighter constituent of the mixture to be separated. In the other embodiment the admitted liquid is a` supplemental liquid whose inflow to the valve is or may be under the control of the operator.

In each of these specic embodiments the valve was necessarily made light and therefore weak. One of the objects of the present invention is to provide a construction, adapted to have modes of. operation like those of mysaid `prior inven` tion, which will permit the use of heavier and stronger valves. Another object of the invention is to provide a construction wherein the opening and closing of the valve may be controlled by the speed of the bowl, the valve remaining tightly closed while the bowl isrotating at a predetermined normal speed but opening when the speed is reduced to or below predetermined lower speed. Thus, as in my said prior application, my object is to control the opening and closing of the valve either automatically or by the operator; but to provide, in either case, an improved construction, and, in the latter mode of control, to avoid, or at least dispense with the necessity of, the use of a supplemental liquid. Another object` of the invention is to provide a construction whereby the opening and closing of the valve may be conu trolled automatically at a predetermined normal speed and may also be controlled by varying the speed of the bowl.

A main feature of the invention comprises a tension device, namely, a spring, or one of the known equivalents of a spring, which tends to move the valve toward the center, whereby the buoyant effect required to open the valve may be reduced and/or the valve may be made heavier by an amount which, acted on by a predetermined centrifugal force, will just overcome the tension of the spring. Another feature of the invention comprises a tension device which tends to move the valve toward the center with a force a little 5 less than the centrifugal force which acts on the valve while the bowl is rotating at a predetermined normal speed, whereby the" valve will remain closed while the bowl is rotating at that speed and will open when the speed is reduced. 'Ihe l0 same valve may be used to allow both modes of operation; but if it is desired to control the opening and closing of the valve solely by the speed of the bowl, the structural features required to allow automatic operation may merely be omitted 15 and the construction thereby simplified.

In the accompanying drawing:

Fig. l is a vertical cross-section through the bowl.

Fig. 2 is an enlarged detail longitudinal sec` 20 tional view of the valve and parts adjacent thereto.

Fig. 3 is` a view, similar to Fig. 2, of one of diierent possible modications.

a is a bowl shell having a top b and containing 25 a tubular feed shaft c, and a nest of separating discs d and a top disc e. The outlet for heavy liquid is at f, for light liquid at y, and for sludge or slimy solids at m. The bowl is supported and driven by a spindle i turning in a bearing a'. The 30 inlet for liquid to be treated is through a tube k.

My `automatic sludge outlet valve comprises a port through the bowl wall, a valve seat m at the inner end of the port and an automatically operating floating valve therefor comprising a radially extending hollow body o having a pointed head n, the tip of which is adapted to Vengage the valve seat and through which tip is a small opening q throttled by a screw The hollow valve body o is slidable radially and may bev 40 guided in any suitable manner, as by a tube p extending from near the bowl wall toward the center of rotation. The end of tube p near the bowl center is closed by a plug s having a hole tthrough which extends a screw u that connects with a'spring 1J attached to the valve body o.

Nuts w on the screw provide means for adjusting the spring to any desired tension.

In the construction shown in Fig. 3 the spring o is in compression between the bowl wall and ashoulder y formed on the valve body.

In operation, if the valve that, in order to have suflicient strength, is made so heavy that a predetermined centrifugal force is greater than .the maximum buoyant eiect of the liquid acting on 'Ill it, has a spring v or v' provided with a tension slightly greater than the excess of centrifugal force over the buoyant eiect, thevalve, while such centrifugal force is operative, will open and shut as if it were lighter. The valve may thus have the same mode of operation as the valve of my prior application.

When oil is fed into the bowl it will ow to the outside and iill back to a circle having the A small quantity of oil will leak past the screw r and through the 'opening q and outlet zc, but

l this will be immediately replaced by oil entering between the valve and the guide tube p. As sludge is separated fromthe oil it will build up y' a layer against the bowl shell and soon cover the end of the tube p and prevent further entrance of oil. In a short time the leakage past the screw 1- will empty the valve, which, being thus lightened, will, under the pull of the spring, oat toward the center of the bowl, thus opening the outlet x. The sludge will then escape through the outlet a: until the end of the tube p is exposed, when oil will again enter and ll the valve and cause it to sink and close the port again, and the cycle will be repeated.

If a heavy valve is provided with a spring having a tension less than the centrifugal force acting on the valve at a predetermined normal speed but greater than that acting at (say) 10% below such normal speed (the relative centrifugal forces at these speeds, which are proportionate to the squares of the speeds, being respectively 100 and 81) the valve will remain tightly closed as long as speed is maintained, but if, before the solids have accumulated to the thickness required to shut 01T access of fluid from the interior of the bowl to the interior of the valve, the speed is reduced to less than 90% of normal, the spring will overcome centrifugal force and move the valve toward the center of the bowl, thus opening the port and allowing the escape of the solids. If the bowl is then speeded up to the speed required to overcom'e the tension of the spring, the valve will again close,

If it is desired to control the closing and opening of the valve solely by the speed of the bowl, this result may be achieved by making no provision for admitting liquid to the interior of the valve and allowing it to constantly escape therefrom; Fig. 3 illustrating such a simplified form of valve. In this construction, means to shut oil ilow of liquid to the space around the valve after accumulation of solids to a predetermined thickness is unnecessary and need not be provided. The solids may be allowed to accumulate to any thickness desired and may be expelled solely by reducing the bowl speed.

In the rst described embodiment of the invention, in which the valve operates automatically, intermittently opening and closing at normal speed and opening and closing also at the will of the operator by changing the speed, it will be understood that, as the bowl slows down when stopping, the valve will open wide and permit discharge of everything in the bowl. This is a highly desirable operation. It, of course, also occurs in that embodiment of the invention in which, from time to time, the accumulated heavy constituent is intermittently discharged, at the will of the operator, bychanging the speed for 5 the limited periods required to eilect such discharge. Another advantage of the invention is that the valve may be allowed to operate automatically for a period of time long enough (say) to handle one tank of oil, and then, by slowing the machine down, completely empty the bowl before starting treatment of another tank of oil having, perhaps, such different characteristics that contamination of one by a little of the other would be objectionable. 15

It will be understod that any desired number of valves may be arranged along diiferent, and preferably uniformly spaced apart, radii of the bowl.

What I claim and desire to protect by Letters Patent is:

1. In a centrifugal bowl provided with a sludge outlet, valve mechanism' including a hollow radially-iloating liquid-receiving member adapted,

at a predetermined Vbowl speed, to move outward to close said outlet or inward to open it dependent on the weight of the liquid, and means providing a passage for flow of liquid from the sepa.- rating chamber of the bowl into said hollow member-said passage being adapted to be shut 301 oi'f by a predetermined thickness of accumulated sludge in the bowl, said valve mechanism also including a tension device tending to movel said hollow member inward.

2. A centrifugal bowl provided with an outlet 351.-

in its peripheral wall, a valve enclosure communicating adjacent said wall with the interior of the bowl and adapted to receive liquid therefrom, a hollow valve member within said enclosure and immersed and floating in said liquid 40 and provided with an opening through which` liquid is admitted from said enclosure to the hollow interior of the valve member, the valve member having an opening through which contained liquid discharges, said valve member being mov- -l able outward to close said outlet and inward to open said outlet, and a tension device tending to move said valve member inward to open saidv outlet.

3. In a centrifugal bowl provided with an outlet, a hollow valve member adapted to iloat in liquid and having openings adapted to receive and discharge liquid and thereby vary its buoyancy and adapted to be moved by centrifugal force into position to close said outlet when containing a suiilcient weight of liquid, and a tension device tending, in opposition to centrifugal force, to move said valve into position to open said outlet.

4. In a centrifugal bowl provided with an outlet, a valve enclosure communicating with the separating chamber of the bowl and adapted to receive liquid therefrom, a hollow valve member in said enclosure and iloatable in liquid admitted to said enclosure, in opposite directions, toward 05` the center of the bowl to open said outlet and toward the periphery of the bowl to close said outlet, a tension device tending to move the valve toward the center of the bowl, means to discharge liquid from the valve member to decrease its weight, and means to admit liquid thereto to increase its weight; whereby the valve member may be made suillciently heavy, by liquid admitted thereto, to close said outlet under a given centrifugal force and may be caused to open said outlet either by reduction of centrifugal force or by discharging a given weight of liquid therefrom'.

5. In a centrifugal bowl provided with a sludge outlet in its periphery, a radially extensive chamber having its outer end in communication with the interior of the bowl, valve mechanism, including a hollow radially-floating member, normally completely surrounded by and illled with liquid in said chamber, adapted, at a predetermined bowl speed, to move outward to close said outlet or inward to open it dependent on the weight of liquid in said member, and means to permit a slow escape of liquid from said member, the communication between the chamber and the interior of the bowl being adapted to be closed by sludge on the accumulation of more than a predetermined amokunt thereof, thus permitting drainage from the member to reduce the weight of liquid therein until it moves inward and opens said outlet to allow escape of sludge and reopening of communication, said valve mechanism in cluding a tension device tending to move said hollow member inward.

6. In a centrifugal bowl provided with a port in its peripheral wall for outow of a heavy separated constituent, a hollow valve body, open at the end most distant from the periphery, radially movable outward to close or inward to open said port, means providing a passage, from near the periphery of the bowl to the open end of the valve adapted to permit ow of a lighter constituent from the bowl body to the interior of the valve when the bowl contains less than a predetermined quantity of a heavier constituent and adapted to be shut off and such flow stopped by said heavier constituent when it exceeds a predetermined quantity, and a spring tending to move the valve toward the center with a force greater than that required to overcome the centrifugal force acting on an empty valve but less than that required to overcome the centrifugal force on a liquid-filled valve.

7. The combination, in a centrifugal bowl provided with a port in its peripheral wall for outilow oi a heavy separated constituent, of a radially movable hollow bodied valve for control of said port, means providing a passage from the in` terior of the bowl to the interior of the valve, the valve having a restricted opening permitting flow from the interior of the valve to exterior of the bowl, with a spring providing a radially inward force greater than the centrifugal force on an empty valve but less than that on a full valve at operating speed of the bowl.

8. The combination, in a centrifugal bowl provided with a port in its peripheral wall for outilow of a heavy separated constituent, of a radially movable hollow bodied valve for control of said port, means providing a passage from the interior of the bowl near its periphery to the interior of the valve near the bowls center, the valve having a restricted opening permitting flow from the interior of the valve to exterior of the bowl, with a spring providing a radially inward force greater than the centrifugal force on an empty valve but less than that on a iull valve at operating speed of the bowl.

9. In a centrifugal bowl provided with an outlet in its peripheral wall, a valve enclosure communicating with the interior of the bowl and adapted to receive liquid therefrom, a hollow valve member in said enclosure and immersed in and radially floatable in said liquid and having openings adapted to receive liquid and discharge liquid and to thereby vary its weight and therefore its buoyancy, said member tending, in the operation of the bowl, due to its own weight and centrifugal force, to float outward into position to close said outlet, and a tension device tending to move the valve member inward and so operating when the power produced by the coaction of centrifugal force and valve weight falls below the minimum required to overcome the tension of the spring.

GEORGE J. STREZYNSKI. 

